Move spec/rubyspec to spec/ruby for consistency

* Other ruby implementations use the spec/ruby directory.
  [Misc #13792] [ruby-core:82287]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59979 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

spec/ruby/library/zlib/gzipreader/each_byte_spec.rb

@@ -0,0 +1,51 @@
+require File.expand_path('../../../../spec_helper', __FILE__)
+require 'stringio'
+require 'zlib'
+
+describe "GzipReader#each_byte" do
+
+  before :each do
+    @data = '12345abcde'
+    @zip = [31, 139, 8, 0, 44, 220, 209, 71, 0, 3, 51, 52, 50, 54, 49, 77,
+            76, 74, 78, 73, 5, 0, 157, 5, 0, 36, 10, 0, 0, 0].pack('C*')
+
+    @io = StringIO.new @zip
+    ScratchPad.clear
+  end
+
+  it "calls the given block for each byte in the stream, passing the byte as an argument" do
+    gz = Zlib::GzipReader.new @io
+
+    ScratchPad.record []
+    gz.each_byte { |b| ScratchPad << b }
+
+    ScratchPad.recorded.should == [49, 50, 51, 52, 53, 97, 98, 99, 100, 101]
+  end
+
+  it "returns an enumerator, which yields each byte in the stream, when no block is passed" do
+    gz = Zlib::GzipReader.new @io
+    enum = gz.each_byte
+
+    ScratchPad.record []
+    while true
+      begin
+        ScratchPad << enum.next
+      rescue StopIteration
+        break
+      end
+    end
+
+    ScratchPad.recorded.should == [49, 50, 51, 52, 53, 97, 98, 99, 100, 101]
+  end
+
+  it "increments position before calling the block" do
+    gz = Zlib::GzipReader.new @io
+
+    i = 1
+    gz.each_byte do |ignore|
+      gz.pos.should == i
+      i += 1
+    end
+  end
+
+end

spec/ruby/library/zlib/gzipreader/each_line_spec.rb

@@ -0,0 +1,5 @@
+require File.expand_path('../shared/each', __FILE__)
+
+describe "GzipReader#each_line" do
+  it_behaves_like :gzipreader_each, :each_line
+end

spec/ruby/library/zlib/gzipreader/each_spec.rb

@@ -0,0 +1,5 @@
+require File.expand_path('../shared/each', __FILE__)
+
+describe "GzipReader#each" do
+  it_behaves_like :gzipreader_each, :each
+end

spec/ruby/library/zlib/gzipreader/eof_spec.rb

@@ -0,0 +1,56 @@
+require File.expand_path('../../../../spec_helper', __FILE__)
+require 'stringio'
+require 'zlib'
+
+describe "GzipReader#eof?" do
+
+  before :each do
+    @data = '{"a":1234}'
+    @zip = [31, 139, 8, 0, 0, 0, 0, 0, 0, 3, 171, 86, 74, 84, 178, 50,
+            52, 50, 54, 169, 5, 0, 196, 20, 118, 213, 10, 0, 0, 0].pack('C*')
+    @io = StringIO.new @zip
+  end
+
+  it "returns true when at EOF" do
+    gz = Zlib::GzipReader.new @io
+    gz.eof?.should be_false
+    gz.read
+    gz.eof?.should be_true
+  end
+
+  it "returns true when at EOF with the exact length of uncompressed data" do
+    gz = Zlib::GzipReader.new @io
+    gz.eof?.should be_false
+    gz.read(10)
+    gz.eof?.should be_true
+  end
+
+  it "returns true when at EOF with a length greater than the size of uncompressed data" do
+    gz = Zlib::GzipReader.new @io
+    gz.eof?.should be_false
+    gz.read(11)
+    gz.eof?.should be_true
+  end
+
+  it "returns false when at EOF when there's data left in the buffer to read" do
+    gz = Zlib::GzipReader.new @io
+    gz.read(9)
+    gz.eof?.should be_false
+    gz.read
+    gz.eof?.should be_true
+  end
+
+  # This is especially important for JRuby, since eof? there
+  # is more than just a simple accessor.
+  it "does not affect the reading data" do
+    gz = Zlib::GzipReader.new @io
+    0.upto(9) do |i|
+      gz.eof?.should be_false
+      gz.read(1).should == @data[i, 1]
+    end
+    gz.eof?.should be_true
+    gz.read().should == ""
+    gz.eof?.should be_true
+  end
+
+end

spec/ruby/library/zlib/gzipreader/getc_spec.rb

@@ -0,0 +1,41 @@
+require File.expand_path('../../../../spec_helper', __FILE__)
+require 'stringio'
+require 'zlib'
+
+describe "GzipReader#getc" do
+
+  before :each do
+    @data = '12345abcde'
+    @zip = [31, 139, 8, 0, 44, 220, 209, 71, 0, 3, 51, 52, 50, 54, 49, 77,
+            76, 74, 78, 73, 5, 0, 157, 5, 0, 36, 10, 0, 0, 0].pack('C*')
+    @io = StringIO.new @zip
+  end
+
+  it "returns the next character from the stream" do
+    gz = Zlib::GzipReader.new @io
+    gz.pos.should == 0
+
+    gz.getc.should == '1'
+    gz.getc.should == '2'
+    gz.getc.should == '3'
+    gz.getc.should == '4'
+    gz.getc.should == '5'
+  end
+
+  it "increments position" do
+    gz = Zlib::GzipReader.new @io
+    (0..@data.size).each do |i|
+      gz.pos.should == i
+      gz.getc
+    end
+  end
+
+  it "returns nil at the end of the stream" do
+    gz = Zlib::GzipReader.new @io
+    gz.read
+    pos = gz.pos
+    gz.getc.should be_nil
+    gz.pos.should == pos
+  end
+
+end

spec/ruby/library/zlib/gzipreader/gets_spec.rb

@@ -0,0 +1,22 @@
+require File.expand_path('../../../../spec_helper', __FILE__)
+require 'zlib'
+require 'stringio'
+
+describe 'GzipReader#gets' do
+  describe 'with "" separator' do
+    it 'reads paragraphs skipping newlines' do
+      # gz contains "\n\n\n\n\n123\n45\n\n\n\n\nabc\nde\n\n\n\n\n"
+      gz = Zlib::GzipReader.new(
+        StringIO.new(
+          [31, 139, 8, 0, 223, 152, 48, 89, 0, 3, 227, 226, 2, 2, 67, 35,
+           99, 46, 19, 83, 16, 139, 43, 49, 41, 153, 43, 37, 21, 204, 4, 0,
+           32, 119, 45, 184, 27, 0, 0, 0].pack('C*')
+        )
+      )
+
+      gz.gets('').should == "123\n45\n\n"
+      gz.gets('').should == "abc\nde\n\n"
+      gz.eof?.should be_true
+    end
+  end
+end

spec/ruby/library/zlib/gzipreader/lineno_spec.rb

@@ -0,0 +1 @@
+require File.expand_path('../../../../spec_helper', __FILE__)

spec/ruby/library/zlib/gzipreader/new_spec.rb

@@ -0,0 +1 @@
+require File.expand_path('../../../../spec_helper', __FILE__)

spec/ruby/library/zlib/gzipreader/open_spec.rb

@@ -0,0 +1 @@
+require File.expand_path('../../../../spec_helper', __FILE__)

spec/ruby/library/zlib/gzipreader/pos_spec.rb

@@ -0,0 +1,27 @@
+require File.expand_path('../../../../spec_helper', __FILE__)
+require 'stringio'
+require 'zlib'
+
+describe "GzipReader#pos" do
+
+  before :each do
+    @data = '12345abcde'
+    @zip = [31, 139, 8, 0, 44, 220, 209, 71, 0, 3, 51, 52, 50, 54, 49, 77,
+            76, 74, 78, 73, 5, 0, 157, 5, 0, 36, 10, 0, 0, 0].pack('C*')
+    @io = StringIO.new @zip
+  end
+
+  it "returns the position" do
+    gz = Zlib::GzipReader.new @io
+
+    gz.pos.should == 0
+
+    gz.read 5
+    gz.pos.should == 5
+
+    gz.read
+    gz.pos.should == @data.length
+  end
+
+end
+

spec/ruby/library/zlib/gzipreader/read_spec.rb

@@ -0,0 +1,68 @@
+require File.expand_path('../../../../spec_helper', __FILE__)
+require 'stringio'
+require 'zlib'
+
+describe "GzipReader#read" do
+
+  before :each do
+    @data = '12345abcde'
+    @zip = [31, 139, 8, 0, 44, 220, 209, 71, 0, 3, 51, 52, 50, 54, 49, 77,
+            76, 74, 78, 73, 5, 0, 157, 5, 0, 36, 10, 0, 0, 0].pack('C*')
+    @io = StringIO.new @zip
+  end
+
+  it "with no arguments reads the entire content of a gzip file" do
+    gz = Zlib::GzipReader.new @io
+    gz.read.should == @data
+  end
+
+  it "with nil length argument reads the entire content of a gzip file" do
+    gz = Zlib::GzipReader.new @io
+    gz.read(nil).should == @data
+  end
+
+  it "reads the contents up to a certain size" do
+    gz = Zlib::GzipReader.new @io
+    gz.read(5).should == @data[0...5]
+    gz.read(5).should == @data[5...10]
+  end
+
+  it "does not accept a negative length to read" do
+    gz = Zlib::GzipReader.new @io
+    lambda {
+      gz.read(-1)
+    }.should raise_error(ArgumentError)
+  end
+
+  it "returns an empty string if a 0 length is given" do
+    gz = Zlib::GzipReader.new @io
+    gz.read(0).should == ""
+  end
+
+  it "respects :external_encoding option" do
+    gz = Zlib::GzipReader.new(@io, external_encoding: 'UTF-8')
+    gz.read.encoding.should == Encoding::UTF_8
+
+    @io.rewind
+    gz = Zlib::GzipReader.new(@io, external_encoding: 'UTF-16LE')
+    gz.read.encoding.should == Encoding::UTF_16LE
+  end
+
+  describe "at the end of data" do
+    it "returns empty string if length prameter is not specified or 0" do
+      gz = Zlib::GzipReader.new @io
+      gz.read # read till the end
+      gz.read(0).should == ""
+      gz.read().should == ""
+      gz.read(nil).should == ""
+    end
+
+    it "returns nil if length prameter is positive" do
+      gz = Zlib::GzipReader.new @io
+      gz.read # read till the end
+      gz.read(1).should be_nil
+      gz.read(2**16).should be_nil
+    end
+  end
+
+end

spec/ruby/library/zlib/gzipreader/readchar_spec.rb

@@ -0,0 +1 @@
+require File.expand_path('../../../../spec_helper', __FILE__)

spec/ruby/library/zlib/gzipreader/readline_spec.rb

@@ -0,0 +1 @@
+require File.expand_path('../../../../spec_helper', __FILE__)

spec/ruby/library/zlib/gzipreader/readlines_spec.rb

@@ -0,0 +1 @@
+require File.expand_path('../../../../spec_helper', __FILE__)

spec/ruby/library/zlib/gzipreader/readpartial_spec.rb

@@ -0,0 +1,17 @@
+require File.expand_path('../../../../spec_helper', __FILE__)
+require 'stringio'
+require 'zlib'
+
+describe 'GzipReader#readpartial' do
+  before :each do
+    @data = '12345abcde'
+    @zip = [31, 139, 8, 0, 44, 220, 209, 71, 0, 3, 51, 52, 50, 54, 49, 77,
+            76, 74, 78, 73, 5, 0, 157, 5, 0, 36, 10, 0, 0, 0].pack('C*')
+    @io = StringIO.new(@zip)
+  end
+
+  it 'accepts nil buffer' do
+    gz = Zlib::GzipReader.new(@io)
+    gz.readpartial(5, nil).should == '12345'
+  end
+end

spec/ruby/library/zlib/gzipreader/rewind_spec.rb

@@ -0,0 +1,48 @@
+require File.expand_path('../../../../spec_helper', __FILE__)
+require 'stringio'
+require 'zlib'
+
+describe "GzipReader#rewind" do
+
+  before :each do
+    @data = '12345abcde'
+    @zip = [31, 139, 8, 0, 44, 220, 209, 71, 0, 3, 51, 52, 50, 54, 49, 77,
+            76, 74, 78, 73, 5, 0, 157, 5, 0, 36, 10, 0, 0, 0].pack('C*')
+    @io = StringIO.new @zip
+    ScratchPad.clear
+  end
+
+  it "resets the position of the stream pointer" do
+    gz = Zlib::GzipReader.new @io
+    gz.read
+    gz.pos.should == @data.length
+
+    gz.rewind
+    gz.pos.should == 0
+    gz.lineno.should == 0
+  end
+
+  it "resets the position of the stream pointer to data previously read" do
+    gz = Zlib::GzipReader.new @io
+    first_read = gz.read
+    gz.rewind
+    first_read.should == gz.read
+  end
+
+  it "invokes seek method on the associated IO object" do
+    # first, prepare the mock object:
+    (obj = mock("io")).should_receive(:get_io).any_number_of_times.and_return(@io)
+    def obj.read(args); get_io.read(args); end
+    def obj.seek(pos, whence = 0)
+      ScratchPad.record :seek
+      get_io.seek(pos, whence)
+    end
+
+    gz = Zlib::GzipReader.new(obj)
+    gz.rewind()
+
+    ScratchPad.recorded.should == :seek
+    gz.pos.should == 0
+    gz.read.should == "12345abcde"
+  end
+end

spec/ruby/library/zlib/gzipreader/shared/each.rb

@@ -0,0 +1,51 @@
+require File.expand_path('../../../../../spec_helper', __FILE__)
+require 'stringio'
+require 'zlib'
+
+describe :gzipreader_each, shared: true do
+
+  before :each do
+    @data = "firstline\nsecondline\n\nforthline"
+    @zip = [31, 139, 8, 0, 244, 125, 128, 88, 2, 255, 75, 203, 44, 42, 46, 201,
+            201, 204, 75, 229, 42, 78, 77, 206, 207, 75, 1, 51, 185, 210,242,
+            139, 74, 50, 64, 76, 0, 180, 54, 61, 111, 31, 0, 0, 0].pack('C*')
+
+    @io = StringIO.new @zip
+    @gzreader = Zlib::GzipReader.new @io
+  end
+
+  after :each do
+    ScratchPad.clear
+  end
+
+  it "calls the given block for each line in the stream, passing the line as an argument" do
+    ScratchPad.record []
+    @gzreader.send(@method) { |b| ScratchPad << b }
+
+    ScratchPad.recorded.should == ["firstline\n", "secondline\n", "\n", "forthline"]
+  end
+
+  it "returns an enumerator, which yields each byte in the stream, when no block is passed" do
+    enum = @gzreader.send(@method)
+
+    ScratchPad.record []
+    while true
+      begin
+        ScratchPad << enum.next
+      rescue StopIteration
+        break
+      end
+    end
+
+    ScratchPad.recorded.should == ["firstline\n", "secondline\n", "\n", "forthline"]
+  end
+
+  it "increments position before calling the block" do
+    i = 0
+    @gzreader.send(@method) do |line|
+      i += line.length
+      @gzreader.pos.should == i
+    end
+  end
+
+end

spec/ruby/library/zlib/gzipreader/tell_spec.rb

@@ -0,0 +1 @@
+require File.expand_path('../../../../spec_helper', __FILE__)

spec/ruby/library/zlib/gzipreader/ungetbyte_spec.rb

@@ -0,0 +1,122 @@
+require File.expand_path('../../../../spec_helper', __FILE__)
+require 'stringio'
+require 'zlib'
+
+describe 'GzipReader#ungetbyte' do
+  before :each do
+    @data = '12345abcde'
+    @zip = [31, 139, 8, 0, 44, 220, 209, 71, 0, 3, 51, 52, 50, 54, 49, 77,
+            76, 74, 78, 73, 5, 0, 157, 5, 0, 36, 10, 0, 0, 0].pack('C*')
+    @io = StringIO.new @zip
+  end
+
+  describe 'at the start of the stream' do
+    before :each do
+      @gz = Zlib::GzipReader.new(@io)
+    end
+
+    describe 'with an integer' do
+      it 'prepends the byte to the stream' do
+        @gz.ungetbyte 0x21
+        @gz.read.should == '!12345abcde'
+      end
+
+      ruby_bug "#13616", ""..."2.6" do
+        it 'decrements pos' do
+          @gz.ungetbyte 0x21
+          @gz.pos.should == -1
+        end
+      end
+    end
+
+    quarantine! do # https://bugs.ruby-lang.org/issues/13675
+      describe 'with nil' do
+        it 'does not prepend anything to the stream' do
+          @gz.ungetbyte nil
+          @gz.read.should == '12345abcde'
+        end
+
+        it 'does not decrement pos' do
+          @gz.ungetbyte nil
+          @gz.pos.should == 0
+        end
+      end
+    end
+  end
+
+  describe 'in the middle of the stream' do
+    before :each do
+      @gz = Zlib::GzipReader.new(@io)
+      @gz.read 5
+    end
+
+    describe 'with an integer' do
+      it 'inserts the corresponding character into the stream' do
+        @gz.ungetbyte 0x21
+        @gz.read.should == '!abcde'
+      end
+
+      it 'decrements pos' do
+        @gz.ungetbyte 0x21
+        @gz.pos.should == 4
+      end
+    end
+
+    quarantine! do # https://bugs.ruby-lang.org/issues/13675
+      describe 'with nil' do
+        it 'does not insert anything into the stream' do
+          @gz.ungetbyte nil
+          @gz.read.should == 'abcde'
+        end
+
+        it 'does not decrement pos' do
+          @gz.ungetbyte nil
+          @gz.pos.should == 5
+        end
+      end
+    end
+  end
+
+  describe 'at the end of the stream' do
+    before :each do
+      @gz = Zlib::GzipReader.new(@io)
+      @gz.read
+    end
+
+    describe 'with an integer' do
+      it 'appends the corresponding character to the stream' do
+        @gz.ungetbyte 0x21
+        @gz.read.should == '!'
+      end
+
+      it 'decrements pos' do
+        @gz.ungetbyte 0x21
+        @gz.pos.should == 9
+      end
+
+      it 'makes eof? false' do
+        @gz.ungetbyte 0x21
+        @gz.eof?.should be_false
+      end
+    end
+
+    quarantine! do # https://bugs.ruby-lang.org/issues/13675
+      describe 'with nil' do
+        it 'does not append anything to the stream' do
+          @gz.ungetbyte nil
+          @gz.read.should == ''
+        end
+
+        it 'does not decrement pos' do
+          @gz.ungetbyte nil
+          @gz.pos.should == 10
+        end
+
+        it 'does not make eof? false' do
+          @gz.ungetbyte nil
+          @gz.eof?.should be_true
+        end
+      end
+    end
+  end
+end

spec/ruby/library/zlib/gzipreader/ungetc_spec.rb

@@ -0,0 +1,292 @@
+require File.expand_path('../../../../spec_helper', __FILE__)
+require 'stringio'
+require 'zlib'
+
+describe 'GzipReader#ungetc' do
+  before :each do
+    @data = '12345abcde'
+    @zip = [31, 139, 8, 0, 44, 220, 209, 71, 0, 3, 51, 52, 50, 54, 49, 77,
+            76, 74, 78, 73, 5, 0, 157, 5, 0, 36, 10, 0, 0, 0].pack('C*')
+    @io = StringIO.new @zip
+  end
+
+  describe 'at the start of the stream' do
+    before :each do
+      @gz = Zlib::GzipReader.new(@io, external_encoding: Encoding::UTF_8)
+    end
+
+    describe 'with a single-byte character' do
+      it 'prepends the character to the stream' do
+        @gz.ungetc 'x'
+        @gz.read.should == 'x12345abcde'
+      end
+
+      ruby_bug "#13616", ""..."2.6" do
+        it 'decrements pos' do
+          @gz.ungetc 'x'
+          @gz.pos.should == -1
+        end
+      end
+    end
+
+    describe 'with a multi-byte character' do
+      it 'prepends the character to the stream' do
+        @gz.ungetc 'ŷ'
+        @gz.read.should == 'ŷ12345abcde'
+      end
+
+      ruby_bug "#13616", ""..."2.6" do
+        it 'decrements pos' do
+          @gz.ungetc 'ŷ'
+          @gz.pos.should == -2
+        end
+      end
+    end
+
+    describe 'with a multi-character string' do
+      it 'prepends the characters to the stream' do
+        @gz.ungetc 'xŷž'
+        @gz.read.should == 'xŷž12345abcde'
+      end
+
+      ruby_bug "#13616", ""..."2.6" do
+        it 'decrements pos' do
+          @gz.ungetc 'xŷž'
+          @gz.pos.should == -5
+        end
+      end
+    end
+
+    describe 'with an integer' do
+      it 'prepends the corresponding character to the stream' do
+        @gz.ungetc 0x21
+        @gz.read.should == '!12345abcde'
+      end
+
+      ruby_bug "#13616", ""..."2.6" do
+        it 'decrements pos' do
+          @gz.ungetc 0x21
+          @gz.pos.should == -1
+        end
+      end
+    end
+
+    describe 'with an empty string' do
+      it 'does not prepend anything to the stream' do
+        @gz.ungetc ''
+        @gz.read.should == '12345abcde'
+      end
+
+      it 'does not decrement pos' do
+        @gz.ungetc ''
+        @gz.pos.should == 0
+      end
+    end
+
+    quarantine! do # https://bugs.ruby-lang.org/issues/13675
+      describe 'with nil' do
+        it 'does not prepend anything to the stream' do
+          @gz.ungetc nil
+          @gz.read.should == '12345abcde'
+        end
+
+        it 'does not decrement pos' do
+          @gz.ungetc nil
+          @gz.pos.should == 0
+        end
+      end
+    end
+  end
+
+  describe 'in the middle of the stream' do
+    before :each do
+      @gz = Zlib::GzipReader.new(@io, external_encoding: Encoding::UTF_8)
+      @gz.read 5
+    end
+
+    describe 'with a single-byte character' do
+      it 'inserts the character into the stream' do
+        @gz.ungetc 'x'
+        @gz.read.should == 'xabcde'
+      end
+
+      it 'decrements pos' do
+        @gz.ungetc 'x'
+        @gz.pos.should == 4
+      end
+    end
+
+    describe 'with a multi-byte character' do
+      it 'inserts the character into the stream' do
+        @gz.ungetc 'ŷ'
+        @gz.read.should == 'ŷabcde'
+      end
+
+      it 'decrements pos' do
+        @gz.ungetc 'ŷ'
+        @gz.pos.should == 3
+      end
+    end
+
+    describe 'with a multi-character string' do
+      it 'inserts the characters into the stream' do
+        @gz.ungetc 'xŷž'
+        @gz.read.should == 'xŷžabcde'
+      end
+
+      it 'decrements pos' do
+        @gz.ungetc 'xŷž'
+        @gz.pos.should == 0
+      end
+    end
+
+    describe 'with an integer' do
+      it 'inserts the corresponding character into the stream' do
+        @gz.ungetc 0x21
+        @gz.read.should == '!abcde'
+      end
+
+      it 'decrements pos' do
+        @gz.ungetc 0x21
+        @gz.pos.should == 4
+      end
+    end
+
+    describe 'with an empty string' do
+      it 'does not insert anything into the stream' do
+        @gz.ungetc ''
+        @gz.read.should == 'abcde'
+      end
+
+      it 'does not decrement pos' do
+        @gz.ungetc ''
+        @gz.pos.should == 5
+      end
+    end
+
+    quarantine! do # https://bugs.ruby-lang.org/issues/13675
+      describe 'with nil' do
+        it 'does not insert anything into the stream' do
+          @gz.ungetc nil
+          @gz.read.should == 'abcde'
+        end
+
+        it 'does not decrement pos' do
+          @gz.ungetc nil
+          @gz.pos.should == 5
+        end
+      end
+    end
+  end
+
+  describe 'at the end of the stream' do
+    before :each do
+      @gz = Zlib::GzipReader.new(@io, external_encoding: Encoding::UTF_8)
+      @gz.read
+    end
+
+    describe 'with a single-byte character' do
+      it 'appends the character to the stream' do
+        @gz.ungetc 'x'
+        @gz.read.should == 'x'
+      end
+
+      it 'decrements pos' do
+        @gz.ungetc 'x'
+        @gz.pos.should == 9
+      end
+
+      it 'makes eof? false' do
+        @gz.ungetc 'x'
+        @gz.eof?.should be_false
+      end
+    end
+
+    describe 'with a multi-byte character' do
+      it 'appends the character to the stream' do
+        @gz.ungetc 'ŷ'
+        @gz.read.should == 'ŷ'
+      end
+
+      it 'decrements pos' do
+        @gz.ungetc 'ŷ'
+        @gz.pos.should == 8
+      end
+
+      it 'makes eof? false' do
+        @gz.ungetc 'ŷ'
+        @gz.eof?.should be_false
+      end
+    end
+
+    describe 'with a multi-character string' do
+      it 'appends the characters to the stream' do
+        @gz.ungetc 'xŷž'
+        @gz.read.should == 'xŷž'
+      end
+
+      it 'decrements pos' do
+        @gz.ungetc 'xŷž'
+        @gz.pos.should == 5
+      end
+
+      it 'makes eof? false' do
+        @gz.ungetc 'xŷž'
+        @gz.eof?.should be_false
+      end
+    end
+
+    describe 'with an integer' do
+      it 'appends the corresponding character to the stream' do
+        @gz.ungetc 0x21
+        @gz.read.should == '!'
+      end
+
+      it 'decrements pos' do
+        @gz.ungetc 0x21
+        @gz.pos.should == 9
+      end
+
+      it 'makes eof? false' do
+        @gz.ungetc 0x21
+        @gz.eof?.should be_false
+      end
+    end
+
+    describe 'with an empty string' do
+      it 'does not append anything to the stream' do
+        @gz.ungetc ''
+        @gz.read.should == ''
+      end
+
+      it 'does not decrement pos' do
+        @gz.ungetc ''
+        @gz.pos.should == 10
+      end
+
+      it 'does not make eof? false' do
+        @gz.ungetc ''
+        @gz.eof?.should be_true
+      end
+    end
+
+    quarantine! do # https://bugs.ruby-lang.org/issues/13675
+      describe 'with nil' do
+        it 'does not append anything to the stream' do
+          @gz.ungetc nil
+          @gz.read.should == ''
+        end
+
+        it 'does not decrement pos' do
+          @gz.ungetc nil
+          @gz.pos.should == 10
+        end
+
+        it 'does not make eof? false' do
+          @gz.ungetc nil
+          @gz.eof?.should be_true
+        end
+      end
+    end
+  end
+end

spec/ruby/library/zlib/gzipreader/unused_spec.rb

@@ -0,0 +1 @@
+require File.expand_path('../../../../spec_helper', __FILE__)